The invention is directed to personal helmets worn for wearer head protection in a number of sports and particularly to an improved aerodynamic helmet which reduces the fluid flow resistance encountered by high speed fluid flow therearound.
There has been a continual evolution of personal helmets used for head protection and many new innovations in helmet design and construction exist in the present state of the helmet art.
Generally speaking, state of the art helmets are designed to provide a smooth or slick curvilinear outer surface with the only rectilinear surface being the lower head entry surface parallel with the shoulder line of the wearer. Helmets are currently manufactured by many different manufactures. Although the principle purpose of the helmet is to protect the head of the wearer and most accomplish this to some degree, the helmet generally has a slick smooth outer surface appearance to the viewer of the helmet to give the impression of low or no resistance to fluid flowing thereacross and to enhance the overall all aesthetic appearance of the wearer and the wearer's surrounding environment.
State of the art helmets include those helmets having the trademarks SHOEI, BELL, BIEFFE, NOLAN, ARAI and others.
FIGS. 1 and 2 depicts a side and front view showing respectfully of a state of the art helmet A manufactured by SHOEI. The helmet shown in FIGS. 1 and 2 has a typical outer shell B design substantially found in all state of the art helmets. In the typical helmet the fluid flow, shown by arrows C, around the outer skin D of the shell B of the helmet tends to follow the surface of the shell including a portion of the trailing or back surface E in the rear of the head of the wearer due to "skin effect". Because of this so called "skin effect" a substantial amount of the fluid flowing past the widest width or transverse portion of the helmet outer surface continues to follow the outer surface toward the back of the helmet for approximately 7 degrees of the diverging helmet surface where the flow then brakes free. This effect creates a considerable amount of turbulence to the fluid flow at the rear of the helmet creating buffeting or vibrating of the helmet and the helmet wearer's head at certain relative helmet and fluid speeds and causing lift to the helmet due to the aerodynamic air flow around the helmet, i.e. airplane wing effect. Considering the fact that the relative speed between the wearer and the surrounding air covers a wide range between say bicycle riders and race car drivers this buffeting or vibrating and lift condition creates a physical discomfort and fatigue to the wearer at all speeds as well as creating a resistance to the fluid flow past the helmet.
Until the emergence of the present invention there has not been a compact or reasonably sized aerodynamicly designed helmet that substantially eliminates the turbulence which causes helmet buffeting or vibrating created by relative fluid flow along the helmet surface and unwanted helmet lift.